The goal of this R01 application is to determine the extent to which patient factors impact on adherence and health outcomes after liver transplantation (LTX). Transplantation is the only option for survival of end stage liver disease; demand far exceeds supply yet little is known about which patients benefit most from the procedure. There are clear links between treatment adherence and health outcomes both in general medicine and in other transplant patient populations. Determining which LTX patients are at risk of non-adherence and suboptimal health outcomes is an ongoing dilemma for clinicians and a significant public health issue; failure to do so is costly to the healthcare system and society. The proposed research will be the first known prospective study of adherence to the multifaceted LTX regimen. Specific aims of this longitudinal study are to 1) prospectively characterize adherence to medication taking, appointment keeping, and recommended lifestyle changes over the first post-txp year and identify latent classes of adherence trajectories; 2) determine salient individual and environmental factors that underlie variation in adherence and predict health outcomes. Adherence will be tracked with interviews, electronic medication monitors, and medical records review over the first year; individual and environmental patient factors will be assessed with self report measures and interviews at 1-2, 6, and 12 months post-transplant; morbidity and, secondarily, mortality will be tracked with medical records review over the remainder of the study period. This study will be conducted in collaboration with the Thomas E. Starzl Institute, at the University of Pittsburgh Medical Center; all adult recipients who survive the acute post-transplant period will be eligible. Recruitment will occur over a 2.5 year period and sample size is projected to be approximately 300 recipients. The long-term goal of this project is to develop guidelines for transplant clinicians to identify patients prior to or early after transplantation who are at risk of non-adherence and sub-optimal health outcomes for targeted patient-specific interventions to maximize benefit of LTX. The application of this research would serve as the basis to advance significantly the nation's capacity to protect and preserve health in transplant populations.